NOTICE! You don't have any audio devices available. It looks like your audio hardware was not recognized by OSS. Please contact 4Front technologies for help (http://www.opensound.com/support.cgi). Don't forget to include your soundon.log file to the support request.

This is probably the reason why no application can play the
sound.

Does anyone know which GTK-package I must have installed?
And why does OSS doesn't recognize any sound device after
reboot? (I did a "init 6")

Either GTK1 or GTK2 developement libraries are needed for ossxmix. I think SUNWgtku or SUNWgtkr are needed. There's a "pkg search" command which could help here. I don't know why it doesn't load on reboot. Hopefully someone else does...